GRUBS
There are several types of white grubs that feed on the roots of lawn grasses. All of them can cause severe damage if left untreated.

OUT OF SIGHT...OUT OF MIND
Grubs live and feed in the soil. It's easy to miss them as they gradually cut the roots out from under your lawn until brown patches begin to appear and the grubs are finally discovered. Pull back the turf if you suspect grubs. If the lawn pulls up easily (like new sod) you may find white grubs in the top inch or so of the soil.

SPRING AND FALL FEEDERS
Grubs are the larval (or worm) state of many types of beetles. The beetles lay their eggs in your lawn, and the newly hatched worms work their way through the thatch and into the soil. Most beetles lay their eggs mid to late summer, and the young grubs do their greatest damage during the fall months. As the weather cools, most grubs burrow into the soil for the winter, and return to the surface to feed again as the soil warms in the spring. After this spring feeding, the grubs pupate into adult beetles and begin the cycle again.

DON'T WAIT
Grubs don't disappear on their own. They should be treated before damage begins to appear, or as soon as they are discovered.